BIOCHEMICAL AND MOLECULAR CHARACTERIZATION OF A NEW SPORADIC GLUCOSE-6-PHOSPHATE-DEHYDROGENASE VARIANT DESCRIBED IN ITALY - G6PD MODENA

A new glucose-6-phosphate dehydrogenase variant detected in an Italian man from the Po delta is described and designated as G6PD Modena. Bio chemical characterization of the variant enzyme revealed an activity 2 1% of normal, a slow electrophoretic mobility, increased K-m value for NADP, decreased K-m value for G6P and a complete absence of NADPH inh ibition, which could account for the apparently nonhaemolytic feature of this variant. The cloning and sequencing of the G6PD Modena allele showed a G --> C transition at nucleotide 844 in exon VIII causing a A sp --> His amino acid substitution. On the basis of biochemical charac terization, G6PD Modena is classified as a genuine variant but it has the same mutation as G6PD Seattle-like.